1. Field of the Invention
The invention relates in general to an inkjet cartridge and a method of identifying the color of ink contained in the cartridge, and more particularly to a method for identifying the colors of ink contained in the cartridge by the color flexible printed circuit board (PCB).
2. Description of the Related Art
The computer printer, particularly the color inkjet printer, has become a necessity in the modern life. It can be used for printing out the desired information such as documents, color pictures, and photos.
Generally, two cartridges are used in the inkjet printer for color printing. One is the black cartridge containing black ink and mostly consumed by printing text documents; the other is the color cartridge containing color inks for printing pictures. Moreover, some types of the inkjet printers are further equipped with the photo-ink cartridges, which can provide abundant hues for printing the high quality photos or pictures. Moreover, the inks with different color are also disposed in the different inkjet cartridges.
FIG. 1 is a partially perspective view of a general inkjet print cartridge. The inkjet print cartridge 150 includes a casing 152, a printhead 154, a printhead chip 156 and a flexible printed circuit board (PCB) 158. There is an ink reservoir 160 in the casing 150 for storing ink (not shown in FIG. 1). The printhead 154, projected out of the bottom of inkjet print cartridge 150. The printhead chip 156 includes a nozzle member comprising two parallel columns of orifices (not shown) formed in the flexible PCB 158. Ink is ejected through the orifices during printing. The flexible PCB 158, attached to the bottom side and back side of the casing 152, is electrically coupled to the printhead chip 156. The printhead chip 156 receives the driving current from the inkjet printer and then makes the cartridge 150 to expel ink. Also, the flexible PCB 158 comprises numerous holes 162, and the dimples of the printer circuit electrically contact with the conductive traces points 164 of the flexible PCB 158 through the holes 162.
Conventionally, the way for the users identifying the color of ink is to read the label 166 posted on the casing 152, or check the color of the lid 168.
The flexible PCB is commonly fabricated by tape automated bonding (TAB) technique. Etching and punching are two typical TAB manufacturing processes. Etching process is characterized by etching the tape while the punching process is characterized by punching the tape to form the holes of the flexible PCB. The details are illustrated in the following description.
FIG. 2A˜FIG. 2J illustrate a conventional etching process for forming the holes of the flexible printed circuit board. First, a substrate 102 such as the material of polyimide (PI) is provided, as shown in FIG. 2A. A copper film 104 is then formed over the substrate 102 by sputtering, as shown in FIG. 2B. Two layers of photo-resist (PR) 106 are formed respectively on the bottom side of the substrate 102 and over the copper film 104, as shown in FIG. 2C. After exposing (FIG. 2D) and developing (FIG. 2E) the two layers of PR 106, the predetermined patterns of the holes and the conductive traces are defined. Next, a copper layer 108 is plated on the exposed copper film 104, and the copper layer 108 and the copper film 104 are integrated as a whole, as shown in FIG. 2F. Then, the substrate 102 is partially etched to form the holes 110, as shown is FIG. 2G. The remaining photo-resist 106 on the both sides are then removed, as shown in FIG. 2H. The copper layer 108 and the copper film 104 are exposed to air, and several gaps 109 are formed on the copper layer 108.
Afterward, the portion of the copper film 104 not covered by the copper layer 108 is removed by photolithography through the steps of coating a layer of PR, exposing, developing and etching. The conductive traces 111 are therefore formed by the combination of the remaining copper film 104 and the copper layer 108, as shown in FIG. 2I. Finally, the conductive trace 111 is enclosed by an insulation layer 112 for the purpose of protection, and the flexible PCB 114 is finished as shown in FIG. 2J. The conventional etching process has several drawbacks, including large time-consumption and low yield rate (high proportion of low-quality product). Also, it produces a sticky precipitate and discharges large amounts of wastewater during etching process. The cost of wastewater treatment and environmental pollution are considerable issues.
FIG. 3A˜FIG. 3I illustrate the conventional punching process for forming the holes of the flexible printed circuit board. First, a substrate 202 is provided (FIG. 3A), and an adhesive layer 204 is coated thereon, as shown in FIG. 3B. Then, the substrate 202 coated with the adhesive layer 204 is punched by the punching tool to form several holes 206, as shown in FIG. 3C. A copper layer 208 is further attached over the adhesive layer 204, as shown in FIG. 3D. Next, a photo-resist layer 210 is formed on the copper layer 208, followed by exposure and development. Numerous gaps 211 are created so as to expose parts of the copper layer 208 to the air, as shown in FIG. 3G. Then, portions of the copper layer 208 not covered by the PR layer 210 are etched, as shown in FIG. 3H.
Afterward, the remaining PR layer 210 is removed, and the discrete copper layer 208 (FIG. 3I) therefore forms the conductive traces. Finally, the conductive trace is enclosed by an insulation layer 212 for the purpose of protection, and then the flexible PCB 214 is completed as shown in FIG. 3I. Compared with the etching process mentioned above, the punching process is a short-term procedure requiring less cost and no wastewater treatment. However, the interval between adjacent holes is too wide to form a large number of holes of the flexible PCB. Consequently the contact area between the printer and the flexible PCB is decreased, and dramatically affects the precision of contact. Furthermore, the punching step could easily cause the breakage of the substrate, thus reducing the yield rate and increasing the cost of production.
Additionally, in the commercial inkjet printer market, there are some kinds of color-separate inkjet print cartridges filled with black ink or color ink, such as cyan ink, magenta ink, yellow ink, light black ink, light cyan ink, light magenta ink and light yellow ink. However, only two conventional methods are used for the identification of color of the ink. That is, if an inkjet print cartridge contains two or more colors of ink, it could be identified either by the colors of lids, marks, or by a label to signify the colors of ink.